Andre Agassi overcame a record number of aces from Joachim Johannson on Sunday and set up an Australian Open quarterfinal against defending champion and top-ranked Roger Federer.
Agassi, an eight-time Grand Slam winner and four-time champion in Melbourne, produced one of his great performances to defeat the 1.98m Johansson, who slammed 51 aces in their 2-hour, 38-minute fourth-round match.
One of the best returners of serve, the 34-year-old Agassi endured Johansson's serves, breaking the Swede three times to win 6-7 (4), 7-6 (5), 7-6 (3), 6-4.
Agassi dropped his own serve twice, at the start of the first and fourth sets, and made only 13 unforced errors in the match -- none in the first set.
"It was a tough day," said Agassi. The 11th-seeded Johansson was pushing the limits on almost every shot. He mixed 66 unforced errors with a remarkable 96 winners, including his aces and service winners. In the first tiebreaker, he clinched the first set with a second service ace at 217kph.
Johansson, 22, surpassed Richard Krajicek's mark of 49 aces in a quarterfinal loss to Russia's Yevgeny Kafelnikov at the 1999 US Open.
Johansson's final three aces came in his last service game.
"Joachim today was hitting the ball so big," Agassi said. "What can you do but sort of react?
"I was anxious the whole time," he added. "I had to stay focused and disciplined, give myself a look and hope I can convert on the few chances I do get."
Quite simply, Agassi said, returning against Johansson "is not fun."
"It's very uncomfortable," he said. "You just have to admire it while you're out there because there's just not a whole lot you can do when destiny is in somebody's hands that extremely."
Two Swedish Johanssons were beaten Sunday. Thomas Johansson, the 2002 Australian Open winner, lost 7-5, 6-3, 6-1 to Slovakia's Dominik Hrbaty.
Federer, whose 11 titles in 2004 included three majors, extended his winning streak to 25 matches with a 6-2, 6-2, 7-6 (4) defeat of Marcos Baghdatis.
Federer has won 48 out of his last 50 matches, and hasn't lost since the second round at the Athens Olympics last August.
Baghdatis broke Federer's serve once and stunned Federer with some brilliant crosscourt forehands in the third set.
Federer, who beat Baghdatis at the last US Open in the 19-year-old Cypriot's only other appearance at a major, fell behind 3-0 in the tiebreaker before reeling off five straight points.
"It's always good to battle it out and win it," Federer said.
Two of Russia's three major title holders are into the quarterfinals.
US Open champion Svetlana Kuznetsova pounded 29 winners to overcome one Russian -- 6-4, 6-2 over Vera Douchevina -- and faces another in the quarterfinals.
Wimbledon champion Maria Sharapova, seeded fourth, will face Kuznetsova next after coming back from a set and a break down to beat Italy's Silvia Farina Elia 4-6, 6-1, 6-2.
Sharapova was using bags of ice to cool off during the change-overs and looked to be in trouble after opening the second by dropping her serve.
But the 17-year-old Sharapova ran off seven consecutive games and broke Farina Elia's last seven service games.
"I'm excited. I know it's going to be another tough match," Sharapova said of Kuznetsova. "I'm prepared. I'm just going to go out like I've been going out and playing my game, having fun, enjoying it and fighting to win."